Half-Loop Antenna Notch Design for Compact Multi-Band Coverage
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Solution Overview
Problem
The challenge is to design a small antenna structure for mobile communication devices that operates within limited space while maintaining good performance, specifically requiring the antenna size to be smaller than one-quarter wavelength of the operating frequency and integrating well with nearby electronic elements.
Innovation Solution
A communication device with a half-loop antenna element, featuring a ground element with a notch and a metal portion extending from it, along with a circuit element group comprising capacitive and inductive elements, which generates resonant modes in specific frequency bands, allowing the antenna to be significantly shorter than traditional loop antennas and covering multiple GSM bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the antenna size is reduced to fit limited space in mobile devices, then the space utilization is improved, but the antenna performance deteriorates
Solution Approach 1:
The patent applies parameter changes by modifying the antenna structure from a traditional full loop to a half-loop configuration with a specific notch geometry. The notch dimensions (long edge at least two times longer than short edge) and the metal portion length (less than 0.18 wavelength) are carefully controlled to achieve resonance at desired frequencies while maintaining compact size. This structural parameter optimization allows the antenna to maintain good performance in a reduced size.
Solution Approach 2:
The circuit element group (capacitive and inductive elements) acts as an intermediary to tune and optimize the antenna's resonant characteristics. These elements compensate for the size reduction by adjusting the electrical length and impedance matching, enabling the compact half-loop structure to achieve the required performance across multiple frequency bands.
2Adaptability or versatility
If more antenna elements are incorporated to provide multiple functions, then the functionality is improved, but the device complexity increases
Solution Approach 1:
The half-loop antenna structure with notch achieves multi-functionality by supporting multiple frequency bands (GSM900, GSM1800, and potentially GSM850, GSM1900) through a single compact design. The notch configuration and circuit element group enable the antenna to resonate at multiple frequencies without requiring separate antenna elements, thus providing universal coverage while maintaining structural simplicity.
Solution Approach 2:
The patent merges the ground element and antenna element into a integrated half-loop structure with the notch, combining multiple functional elements into a single compact unit. This integration reduces the overall complexity compared to using separate antenna elements for different frequency bands.
3Length of moving object
If the antenna length is reduced below one-quarter wavelength, then the compactness is improved, but the resonant performance deteriorates
Solution Approach 1:
The patent successfully reduces the antenna length below one-quarter wavelength by changing the structural parameters: using a half-loop configuration with a notch where the metal portion length is less than 0.18 wavelength. The notch geometry (with long edge at least two times longer than short edge) and the circuit element group work together to maintain resonant performance despite the reduced length, achieving compactness without sacrificing resonant capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables a compact antenna structure that effectively covers multiple frequency bands (GSM900/1800 and potentially GSM850/1900) with improved impedance matching and efficiency, maintaining performance without the need for altering the antenna's dimensions, thus addressing the space constraints in mobile devices.
Implementation Method 1
a circuit element group comprising at least a capacitive element and an inductive element, the capacitive element and the inductive element connected in series and coupled to the feeding element, the circuit element group causing generation of a first resonant mode in a first operating band of the antenna element
Data Source
AI summary
A communication device including an antenna structure is provided, wherein the antenna structure includes a ground element, an antenna element, and a circuit element group. The ground element has a notch at one of its edges, and a long edge of the notch is at least two times longer than a short edge of the notch. The antenna element includes a metal portion disposed in the notch. Two ends of the metal portion are extended away from each other and are positioned substantially at or around two opposite edges of the notch. One end of the metal portion is coupled to the ground element, and the other end of the metal portion is a feeding terminal of the antenna element. The circuit element group includes at least a capacitive element and an inductive element.